This invention concerns an anode assembly for an x-ray tube, and especially a miniature x-ray tube.
X-ray tubes are described in U.S. Pat. Nos. 4,143,275, 5,153,900, 5,428,658, 5,422,926, 5,422,678, 5,452,720, 5,621,780, RE 34,421 and 6,319,188, some of which pertain to miniature x-ray tubes. The term miniature x-ray tube as used herein is intended to mean an x-ray tube of about 10 mm. diameter or less, useful for therapeutic and diagnostic medical purposes, and materials analysis, among other uses.
The anode of an x-ray tube is a critical element. For a number of applications the anode should transmit x-rays through itself to provide a wide angular range for emission of x-rays from the tube, rather than emitting the x-rays only in the generally radial direction.
Xoft microTube U.S. Pat. No. 6,319,188, referenced above, describes a miniature x-ray tube in which the anode is generally flat, with provision for x-ray emission through various angular ranges in different embodiments.
Other patents having some relevance to this invention include U.S. Pat. Nos. 3,584,219, 5,369,679, 5,528,652, 5,566,221, RE 35,383, 6,095,966, 6,134,300, and Int'l Pub. WO 97/07740.
It is an object of this invention to improve the geometry and the structure of an anode assembly in an x-ray tube, providing a wide angle of emission, without compromising x-ray output, seal integrity or efficiency, and to provide an efficient placement for a getter, necessary for tube longevity.